Method of producing gamma-halogeno-delta unsaturated carboxylic acid esters

ABSTRACT

Novel γ-lactone derivatives are provided. These lactone derivatives, when reacted with hydrogen halide in alcohol, yield γ-halogeno-δ-unsaturated carboxylic acid esters. This ring-opening process is useful for the purpose of increasing the yield of pyrethrin analogs which are of value as insecticides and agricultural chemicals. Thus, the γ-lactone derivatives by-produced in the production process for dihalogenovinyl chrysanthemumates are caused to undergo ring-opening reaction to yield the corresponding γ-halogeno-δ-unsaturated carboxylic acid esters which are important intermediates for said pyrethrin analogs.

This application is a continuation of application Ser. No. 840,279,filed Oct. 7, 1977, now abandoned, which in turn is a division ofapplication Ser. No. 705,176, filed July, 14, 1976 now abandoned.

The present invention relates, in one aspect, to novel γ-lactonederivatives which can be converted to γ-halogeno-δ-unsaturatedcarboxylic acid esters of value as intermediates for the synthesis ofsubstituted cyclopropanecarboxylic acid esters and, in another aspect,to a method for producing said γ-halogeno-δ-unsaturated carboxylic acidesters from said γ-lactone derivatives.

A principal object of the present invention is to provide a methodwhereby the γ-lactone derivatives by-produced in the production processfor dihalogenovinyl chrysanthemumates, which are currently attractingmuch attention as insecticides and agricultural chemicals, are permittedto undergo a ring-opening reaction to yield the correspondingγ-halogeno-δ-unsaturated carboxylic acid esters. Another object is toincrease the yield of cyclopropanecarboxylic acid esters fordihalogenovinyl chrysanthemumates by means of said method, as willhereinafter be described in detail.

The γ-lactone derivatives according to the present invention arerepresented by the following general formula (I): ##STR1## (wherein R¹and R², respectively, mean a lower alkyl group of 1 to 5 carbon atoms;R³ is selected from the class consisting of hydrogen, alkyl groups of 1to 5 carbon atoms and cycloalkyl groups of 3 to 8 carbon atoms; Y is Xor --CHX--CH₃ ; and Xs are the same or different halogen atoms).

Referring to general formula (I), R¹ and R², respectively, mean a loweralkyl group of 1 to 5 carbon atoms, being preferably methyl, ethyl,propyl or neopentyl. R³ is a hydrogen atom, an alkyl group of 1 to 5carbon atoms or a cycloalkyl group of 3 to 8 carbon atoms, preferablyhydrogen, methyl, ethyl, propyl or cyclohexyl. X is chlorine, bromine,fluorine or iodine, preferably a chlorine or bromine atom. Y is said Xor --CHX--CH₃, preferably chlorine, bromine, 1-chloroethyl or1-bromomethyl.

When the ease of conversion to the correspondingγ-halogeno-δ-unsaturated carboxylic acid esters and the ease ofconversion to cyclopropanecarboxylic acid esters for dihalogenovinylchrysanthemumates are taken into consideration, the preferred members ofthe γ-lactone derivative of general formula (I) are those γ-lactonederivatives which may be represented by the following general formula(I'): ##STR2## (wherein X has the same meaning as defined for generalformula (I); R^(3') is a member of the class consisting of hydrogen andalkyl groups of 1 to 5 carbon atoms). Typical species of the preferredγ-lactone derivatives are as follows. ##STR3##

In the present invention, a γ-lactone derivative of general formula (I)is reacted with a hydrogen halide and an alcohol having the followinggeneral formula (II):

    R.sup.4 OH                                                 (II)

to obtain a γ-halogeno-δ-unsaturated carboxylic acid ester of thefollowing general formula (III): ##STR4## easily and in high yield.(Referring to the above general formulas (II) and (III), R⁴ is analcohol residue; and R¹, R², R³, X and Y in general formula (III) havethe same meanings as respectively defined for general formula (I)).

As examples of the alcohol (R⁴ OH) used herein, there may be mentionedthe alcohols whose residues R⁴ (i.e. the residue after removal of ahydroxyl group from each alcohol) are alkyl groups, cycloalkyl groups,alkenyl groups, cycloalkenyl groups, alkynyl groups, ##STR5## (whereinR⁵ is hydrogen or methyl; R⁶ is alkenyl, alkadienyl, alkynyl or benzyl),##STR6## (wherein R⁷ is hydrogen, ethynyl or cyano; R⁸ is hydrogen,halogen or alkyl; R⁹ is halogen, alkyl, alkenyl, alkynyl, benzyl,thenyl, furylmethyl, phenoxy or phenylthio; R⁸ and R⁹, taken together,may represent a polymethylene group which may optionally be interruptedby a sulfur or oxygen atom; Q is --O--, --NH--, --S-- or --CH═CH--; n is1 or 2), A--CH₂ -- (wherein A is phenoxyphenyl, phthalimido,thiphthalimido, di- or tetrahydrophthalimido or dialkylmaleimide),##STR7## (wherein R¹⁰ is phenyl, thienyl or furyl; B is halogen) and soforth. Preferred are alcohols whose residues are lower alkyl groups suchas methyl and ethyl. More particularly, there may be mentioned methanol,ethanol, propanol, butanol, octanol, benzyl alcohol, 3-phenoxybenzylalcohol, allethrolone, pyrethrolone, 5-benzyl-3-furylmethyl alcohol,5-phenoxyfurfuryl alcohol, 4-phenyl-2-butyn-1-ol and so forth, althoughlower alcohols such as methoanol, ethanol, propanol, butanol, etc. areespecially desirable. The amount of such alcohol may be at least 0.5times the stoichiometric amount necessary for the ring-openingesterification of γ-lactone derivative (I). However, generally 0.5 to 10molecular equivalents and preferably 1.5 to 7 molecular equivalents ofthe alcohol is employed. If desired, the alcohol may be used in largeexcess, e.g. 10 molecular equivalents or more, so that it may act alsoas the solvent.

As the hydrogen halide, there may be mentioned hydrogen chloride,hydrogen bromide, hydrogen iodide and hydrogen fluoride, althoughhydrogen chloride and hydrogen bromide are preferred.

The amount of said hydrogen halide may range from 0.5 to 10 times thestoichiometric amount necessary for the ring-opening reaction ofγ-lactone derivative (I), the range of 1.3 to 5 molecular equivalentsbeing preferred.

This reaction may be carried out in an open system or in a closedsystem, within the temperature range of 0° to 150° C. Where the amountof hydrogen halide is not less than about twice the stoichiometricamount necessary for the ring-opening reaction of γ-lactone derivative(I), quite satisfactory results may be obtained by conducting thereaction at a temperature between 0° C. and room temperature (about 30°C.) and in an open system. Where the amount of hydrogen halide is lessthan twice said stoichiometric amount, the reaction is preferablyconducted in a closed system at a temperature in the range of 50° to100° C.

In conducting this ring-opening esterification reaction, the reactor maybe charged with the starting material γ-lactone derivative, hydrogenhalide and alcohol in an optional order but it is preferable either: (A)to let the hydrogen halide be absorbed into the alcohol and, then, addthe starting material γ-lactone derivative to the solution or (B) to addthe hydrogen halide to a mixture of the alcohol and starting materialγ-lactone derivative.

After the reaction has been completed, the reaction mixture may bedirectly subjected to distillation to recover the excess hydrogen halideand alcohol. Then, the residue may be further distilled under reducedpressure to obtain the contemplated γ-halogeno-δ-unsaturated carboxylicacid ester.

The γ-halogeno-δ-unsaturated carboxylic acid ester of general formula(III) is especially of value as intermediates for the synthesis ofcyclopropanecarboxylic acid esters for dihalogenovinyl chrysanthemumateshaving strong insecticidal activity. Thus, by treating aγ-halogeno-δ-unsaturated carboxylic acid ester of general formula (III)with an organic or inorganic basic reagent, there can be produced acyclopropanecarboxylic acid ester of the following general formula (IV):##STR8##

Referring to the above general formula (IV), R¹, R², R³, X and Y havethe same meanings as respctively defined for general formula (I) andR^(4') is an alcohol residue which may be either the same as ordifferent from R⁴, provided that even where R^(4') is an alcohol residuedifferent from R⁴, the former alcohol residue is preferably one of thosementioned for R⁴.

As examples of the basic reagent used as above, there may be mentionedalkali metal hydroxides such as sodium hydroxide, potassium hydroxide,etc.; alkali metal alcoholates such as sodium methylate, sodiumethylate, potassium methylate, potassium ethylate, sodium n-propylate,sodium n-butylate, sodium t-butylate, sodium isoamylate, potassiumt-butylate, potassium isoamylate, etc.; nitrogen-containing organicbases such as 1,5-diazabicyclo[3,4,0]nonene-5 (DBN),1,5-diazabicyclo[5,4,0]undecene-5(DBU),1,4-diazabicyclo[2,2,2]octane(DABCO), 2-dimethylamino-1-pyrroline,5-methyl-1-azabicyclo[3,3,0]octane, etc.; organolithium compounds suchas n-butyllithium, sec-butyllithium, diisopropylaminolithium,dicyclohexylaminolithium, etc.; sodium hydride, sodium amide, sodiummetal, etc.; by way of example. Treatment with such a basic reagent maygenerally be carried out at a temperature between about -80° C. andabout 150° C. but where an alkali metal alcoholate, alkali metalhydroxide or a nitrogen-containing organic base is employed, thistreatment is preferably carried out at about 0° C. to about 100° C. orwhen sodium hydride or sodium amide, for instance, is employed, thepreferred temperature range is from -70° C. to about 25° C. Thistreatment with a basic reagent does not always require the use of asolvent but, if desired, use may be made of a solvent inert to thereaction or a solvent which does not interfere with the reaction, suchas ethyl ether, tetrahydrofuran, benzene, chlorobenzene, toluene,methanol, ethanol, propanol, butanol, n-hexane, n-octane, carbontetrachloride, methylene chloride, ethyl acetate, acetonitrile or thelike. Generally, the basic reagent is used preferably in a proportion ofabout 0.3 mole to about 7 moles per mole or starting material ester, butwhen a nitrogen-containing organic base is employed, it may be used inlarge excess so that it will act also as the solvent.

The cyclopropanecarboxylic acid ester which is produced upon treatmentwith such a basic reagent does not always possess the same alcoholresidue as that of the starting material ester used in the treatmentwith basic reagent but when an alcohol not corresponding to the alcoholresidue in the starting material ester is used as the solvent, forinstance, there is normally produced a cylcopropanecarboxylic acid esterpossessing the alcohol residue derived from the solvent alcohol as theresult of transesterification with the solvent alcohol. Also, where analkali metal alcoholate is employed as the basic reagent, there may beproduced a cyclopropanecarboxylic acid ester possessing the alcoholresidue derived from said alkali metal alcoholate.

Cyclopropanecarboxylic acid esters of general formula (IV) areinsecticides or synthetic intermediates thereof. The allethronyl ester,pyrethronyl ester, 3-phenoxybenzyl ester, 5-benzyl-3-furylmethyl ester,etc. of 2,2-dimethyl-3-(2',2'-dihalogenovinyl) cyclopropanecarboxylicacid, in particular, are insecticidally more than several times asactive as the corresponding esters of crysanthemummonocarboxylic acid,their stability against light being also higher. These compounds, infact, are pyrethrin analogs which are currently attracting muchattention (European Chemical News, November 23, 39 (1973); M. Elliot etal, Nature 244, 456 (1973); D. G. Brown et al, J. Agr. Good Chem. 21,No. 5, 767 (1973)).

Heretofore known, for the production of lower alkyl esters of2,2-dimethyl-3-(2',2'-dihalogenovinyl) cyclopropanecarboxylic acids, isa method in which a lower alkyl ester of3-formyl-2,2-dimethylcyclopropanecarboxylic acid which is obtainable byozonolysis of the lower alkyl ester of chrysantemummonocarboxylic acidis subjected to Wittig reaction (Japanese Patent Application Laid OpenNo. 47531/1974, corres. to German Pat. Laid Open No. 2326077) but thismethod is not commerically advantageous partly because the startingmaterial chrysanthemummonocarboxylic acid lower alkyl ester is expensiveand partly because the method involves the use of a costly phsophoruscompound.

Farkas et al added a diazoacetic acid ester to1,1-dichloro-4-methyl-1,3-pentadiene to obtain a2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylic acid ester(J. Farkas et al, Collect. Czech. Chem. Commun., 24, 2230 (1959)). Thisprocess was not commercially profitable, either, partly because itprovides only low yields and entails a danger of explosion and partlybecause the starting material 1,1-dichloro-4-methyl-1,3-pentadiene isnot easy to be prepared.

We previously made an intensive study for the establishment of anindustrial process for producing various substituted cyclopropanederivatives including 2,2-dimethyl-3-(2',2'-dihalogenovinyl)cyclopropanecarboxylic acids and/or their esters and ultimatelydiscovered a method for producing cyclopropanecarboxylic acid esters ofgeneral formula (IV) which comprises treating an ester of said generalformula (III) and/or an ester of general formula (V): ##STR9## (whereinR¹, R², R³, R⁴, X and Y have the same meanings as respectively definedfor general formula (III)) with a basic reagent. This treatment with abasic reagent can be carried out in the same manner as the treatment ofsaid esters of general formula (III) with a basic reagent. The esters ofgeneral formula (III) and/or the esters of general formula (V) can beproduced by the procedure shown below by way of reaction formulas##STR10## (R¹, R², X and Y in general formula (VI) and R³ and R⁴ ingeneral formula (VII) have the same meanings as respectively defined forgeneral formulas (III) and (V)). Taking the production of2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylic acid esteras an example, isobutene and chloral are first reacted together toobtain 1,1,1-trichloro-4-methyl-4-penten-2-ol which, in turn, isisomerized to 1,1,1-trichloro-4-methyl-3-penten-2-ol. This1,1,1-trichloro-4-methyl-3-penten-2-ol is reacted with an orthoaceticacid ester to obtain a 3,3-dimethyl-4,6,6-trichloro-5-hexenoic acidester and/or a 3,3 -dimethyl-6,6,6-trichloro-4-hexenoic acid ester,which is then treated with a basic reagent. By the above procedure canbe obtained the desired 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylic acid ester. If a different orthocarboxylic acidester is used in lieu of said orthoacetic acid ester, there is obtaineda 1-substituted-2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylic acid ester via the corresponding2-substiuted-3,3-dimethyl-6,6,6-trichloro-4-hexenoic acid ester and/or2-substituted-3,3-dimethyl-4,6,6-trichloro-5-hexenoic acid ester. Forexample, where an orthopropionic acid ester is employed, there isobtained a 1,2,2-trimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylic acid ester via a2,3,3-trimethyl-6,6,6-trichloro-4-hexenoic acd ester and/or a2,3,3-trimethyl-4,6,6-trichloro-5-hexenoic acid ester, Recently, theprocess has been proposed which comprises reacting 3-methyl-2-buten-1-olwith an orthoacetic acid ester to obtain a 3,3-dimethyl-4-pentenoic acidester, adding a carbon tetrahalide to the last-mentioned ester to obtaina 3,3-dimethyl-4,6,6,6-tetrahalogenohexanoic acid ester and finallytreating it with a basic reagent to produce a2,2-dimethyl-3-(2',2'-dihalogenovinyl) cyclopropanecarboxylic acid ester(The 31st Fall Congress of Japanese Chemical Society, Kondo et al, ACollection of Manuscripts, 58 (1974). In the above process, too, byreplacing said 3,3-dimethyl-4-pentenoic acid ester with another3,3-dialkyl-4-pentenoic acid ester and said orthoacetic acid ester witha different orthocarboxylic acid ester, there can be obtained thecorresponding 2-substituted-3,3-dialkyl-4,6,6,6-tetrahalogenohexanoicacid ester of general formula (VIII): ##STR11## (wherein R¹, R², R³, R⁴and X have the same meanings as respectively defined for general formula(III)). This compound may be reacted with a basic reagent to obtain acyclopropanecarboxylic acid ester of general formula (IV). Thistreatment with a basic reagent is carried out in the same manner as thetreatment of ester (III) with a basic reagent.

As has been described hereinbefore, all the ester of general formula(III), the ester of general formula (V) and the ester of general formula(VIII), when treated with a basic reagent, undergo ring closure to yieldsubstituted cylcopropane derivatives of the type represented by generalformula (IV). Analysis of the byproducts formed in the reactionsrevealed the presence of γ-lactone derivatives of general formula (I).

The reaction of an allylic alcohol of said general formula (VI) with anorthocarboxylic acid ester of general formula (VII) is carried out inthe presence or absence of an acid catalyst and at temperatures in therange of 100° to 200° C., preferably, between 120° and 160° C. It hasbeen found that, in this reaction, too, a γ-lactone derivative ofgeneral formula (I) is byproduced in a maximum yield of about 60 percentdepending on the conditions of the reaction. As preferred examples ofthe acid catalyst to be thus employable, there may be mentioned formicacid, propionic acid, isobutyric acid, cyclohexanecarboxylic acid,adipic acid, benzoic acid, phenol, cresol, hydroquinone,p-toluenesulfonic acid, benzenesulfonic acid, sulfuric acid,hydrochloric acid, phsophoric acid, boric acid and so forth, althouthother similar acid catalysts may also be employed.

It has also been found that, in the treatment of ester (III), (V) or(VIII) with a basic reagent, said γ-lactone derivative (I) is producedin a large amount if water is present in the reaction system.

The ring-opening osterification ((I)→(III)) according to the presentinvention is very useful for the conversion of such a byproduct orconcomitant product γ-lactone derivative to an ester of general formula(III) which may be easily caused to cyclize to a cyclopropanecarboxylicacid ester of the type represented by general formula (IV).

Therefore, the production economics of cyclopropanecarboxylic acidesters can be improved by modifying the production process ofcyclopropanecarboxylic acids and incorporating the ring-openingesterification according to the present invention more positively in theoverall production flow as will be described hereinafter.

Aafter detailed investigations, it has been found that if the treatmentof each of esters (III), (V) and (VIII) with a basic reagent is followedby treatment of the reaction mixture with an acid reagent, there arecases in which a free carboxylic acid of general formula (IX) ##STR12##(wherein R¹, R², R³, X and Y have the same meanings as respectivelydefined for general formula (I)) is produced by the acidification of thesalt of carboxylic acid (IX) which is present in the reaction systemand/or by hydrolysis of at least a portion of an ester of the typerepresented by general formula (IV) which is also present in thereaction system. After all, as the cyclopropanecarboxylic acidderivative, there are obtained a carboxylic acid of general formula (IX)and/or an ester thereof (an ester of the type represented by generalformula (IV). Moreover, it has also been found that γ-lactonederivatives of general formula (I) are produced in amounts exceedingthose obtainable without said acid treatment, while entailing nosubstantial reduction in the yield of such cyclopropanecarboxylic acidderivatives. The output of such a γ-lactone derivative of generalformula (I) varies according to the conditions used in the cyclizationreaction of the starting material ester, especially the species of basicreagent used in that procedure. For example, even where an alkali metalalcoholate is used as the basic reagent, there is produced saidγ-lactone derivative in a yield of about 4 to 10 percent, which is arelatively conservative figure, and where said basic reagent is analkali metal hydroxide which is less costly and easier to handle incommerical runs, the yield may be as high as about 50 percent.

Thus, the process which, as described below, combines the abovetreatment for increasing the yield of γ-lactone derivatives withoutdecreases in the yield of cyclopropanecarboxylic acid derivatives withthe ring-opening esterification of such γ-lactone derivatives, includingthe step of recycling the ring-opening esterification product to thecyclization reaction stage, is conducive to an improved productioneconomics of cyclopropanecarboxylic acid derivatives.

Thus, an ester selected from the class consisting of the esters ofgeneral formula (III), esters of general formula (V) and esters ofgeneral formula (VIII), or a mixture of such esters, is treated with abasic reagent and, then, with an acid reagent to obtain acyclopropanecarboxylic acid derivative comprising acyclopropanecarboxylic acid of general formula (IX) and/or an esterthereof (IV) and a γ-lactone derivative of general formula (I).

Then, (Process i) this γ-lactone derivative (I), together with saidcyclopropanecarboxylic acid derivative, is treated with a hydrogenhalide and an alcohol of general formula (II). From the reaction mixtureis recovered a cyclopropanecarboxylic acid ester of general formula(IV), while the concomitantly produced ester of general formula (III) istreated with a basic reagent and, if necessary, further treated with anacid reagent to obtain an additional amount of cyclopropanecarboxylicacid derivative which is a cyclopropanecarboxylic acid of generalformula (IX) and/or an ester thereof (IV).

In an alternative process (Process ii), said cyclopropanecarboxylic acidderivative is recovered independently of said γ-lactone derivative ofgeneral formula (I), while the latter γ-lactone derivative (I) isreacted with a hydrogen halide and an alcohol of general formula (II)and the resultant ester of general formula (III) is treated with a basicreagent and, if necessary, with an acid reagent to obtain an additionalamount of cyclopropanecarboxylic acid derivative consisting of acyclopropanecarboxylic acid of general formula (IX) and/or an esterthereof (IV). Accordingly, the overall yield of saidcyclopropanecarboxylic acid derivative is markedly increased and,therefore, the economics of the production process is improved. In thisconnection, the treatment of an ester selected from the class consistingof the esters of general formula (III), esters of general formula (V)and esters of general formula (VIII) or a mixture of such esters with abasic reagent may be carried out in the same manner as the treatmentwith a basic reagent which has been described hereinbefore.

The product obtainable by the above treatment with a basic reagentcontains a precursor (its structure remains yet to be elucidated) ofγ-lactone derivative (I), in addition to said ester ofcyclopropanecarboxylic acid (VII). Moreover, in certain cases, saidproduct further contains a salt of cyclopropanecarboxylic acid (VII). Ifthis treatment with a basic reagent is followed by treatment with anacid reagent in order to neutralize or acidify the reaction system,there are obtained the cyclopropanecarboxylic acid derivative consistingof cyclopropanecarboxylic acid (VII) and/or its ester and a γ-lactonederivative (I). As preferred examples of the acid reagent thusemployable, there may be mentioned hydrogen chloride, hydrogen bromide,phosphoric acid, sulfuric acid, formic acid, acetic acid,monochloroacetic acid, phenol, p-toluenesulfonic acid and so forth,although other similar acid reagents may also be employed. Theproportion of such acid reagent may be just enough to neutralize thereaction mixture following the treatment with a basic reagent. However,it is not objectionable to acidify the reaction mixture using a slightexcess of acid reagent. While there are no particular limits to thetemperature of this acid treatment, the treatment is preferablyconducted at a temperature not exceeding 40° C. so as to inhibithydrolysis of the ester of cyclopropanecarboxylic acid (VII) or otherside reactions.

In the present invention, the aforementioned γ-lactone derivative (I) isreacted with a hydrogen halide and an alcohol (II) to obtain thecorresponding ester of general formula (III). This reaction is effected:(a) by permitting a hydrogen halide and an alcohol to act upon themixture of cyclopropanecarboxylic acid derivative and γ-lactonederivative (I) obtained by said treatment with an acid reagent or (b) byseparating said cyclopropanecarboxylic acid derivative from γ-lactonederivative (I) and permitting a hydrogen halide and an alcohol to actupon the γ-lactone derivative (I) thus isolated. The order of chargingthe hydrogen halide and alcohol has already been described hereinbefore.Generally, it is desirable: (A) to introduce a hydrogen halide into thealcohol and, then, add said γ-lactone derivative (I) or said mixture ofγ-lactone derivative (I) and cyclopropanecarboxylic acid derivative tothe above-obtained alcohol solution or (B) to add the hydrogen halide toa system in which both said alcohol and said γ-lactone derivative (I) orsaid mixture of γ-lactone derivative (I) and cyclopropanecarboxylic acidderivative are present. While the alcohol is is preferably a loweralcohol such as methanol, ethanol, propanol, butanol or the like, otheralcohols within the ambit of general formula (II) may be employed, ifdesired. The proportion of alcohol has already been mentioned, but wherethe system includes a cyclopropanecarboxylic acid (II), it is preferableto employ about 0.5 to 10 times the stoichiometric amount of alcoholnecessary for the ring-opening esterification of γ-lactone derivativeand the esterification of the cyclopropanecarboxylic acid. Otherconditions of reaction have already been described hereinbefore.

After the above reaction, if there are residues of hydrogen halideand/or alcohol, these are separated and recovered, e.g. by distillation,followed by further distillation of the residue under reduced pressure.By this procedure is obtained, in the case of the above (Process ii),the ester of general formula (III) which is the product of reaction ofγ-lactone derivative with hydrogen halide and alcohol, whereas in thecase of (Process i), there is obtained the ester of general formula(III) together with the ester of cyclopropanecarboxylic acid (IX). Theester of general formula (III) and ester of cyclopropanecarboxylic acid(IX) thus obtained are the esters possessing the alcohol residueoriginating from the alcohol used in the ring-opening esterification ofγ-lactone derivative (I) and/or the ester supplied to this reactionsystem, the composition thereof being variable according to such factorsas the composition of the cyclopropanecarboxylic acid derivative fed tothis reaction system and the species and amount of alcohol used in thereaction.

The ester of general formula (III) thus obtained from byproductγ-lactone derivative (I) is treated with a basic reagent and, ifnecessary, further with an acid reagent, whereby an additional amount ofcyclopropanecarboxylic acid derivative (cyclopropanecarboxylic acid (IX)and/or its ester) is obtained. These treatments with a basic reagent andwith an acid reagent may be carried out in the same manner as thecorresponding treatments of starting ester with such reagents which havebeen described hereinbefore.

Only for the purpose of assisting in the understanding of theabove-mentioned (Process i) and (Process ii), a few working exampleswill be schematically described. In the following formulas, Me means amethyl group and Et means an ethyl group. ##STR13##

Particularly where, among said basic reagents, an alkali metal hydroxideis employed (in this case, the total yield of saidcyclopropanecarboxylic acid derivative and γ-lactone derivative ismaximal, whereas other byproducts are substantially absent), theγ-lactone derivative (I) may also be effectively utilized by thefollowing procedure to obtain the cyclopropanecarboxylic acid ester (IV)in good yield.

Thus, an ester selected from the class consisting of the esters ofgeneral formula (III), esters of general formula (V) and esters ofgeneral formula (VIII) or a mixture of such esters is treated with analkali metal hydroxide and, then, with an acid reagent to obtain acyclopropanecarboxylic acid derivative consisting ofcyclopropanecarboxylic acid (IX) and its ester (IV) and a γ-lactonederivative of general formula (I). Then, (Process iii) thiscyclopropanecarboxylic acid derivative, together with said γ-lactonederivative, is heated with an alcohol (II) in the presence of an acidcatalyst and, from the resultant reaction mixture, thecyclopropanecarboxylic acid ester of general formula (IV) is separatedfrom the γ-lactone derivative of general formula (I) and recovered,whereas the γ-lactone derivative (I) is reacted with a hydrogen halideand an alcohol (II) to obtain an ester of general formula (III), which,in turn, is treated with an alkali metal hydroxide and, then, with anacid reagent. The thus-obtained mixture of a cyclopropanecarboxylic acidderivative consisting of a cyclopropanecarboxylic acid of generalformula (IX) and an ester thereof (IV) and a γ-lactone derivative ofgeneral formula (I) is heated together with an alcohol (II) in thepresence of an acid catalyst, followed by separation of an additionalamount of cyclopropanecarboxylic acid ester (IV). The above treatment ofan ester selected from the class consisting of the esters of generalformula (III), esters of general formula (V) and esters of generalformula (VIII) or a mixture of such esters with an alkali metalhydroxide may be carried out in the same manner as the treatment with abasic reagent which has already been described hereinbefore. Thetreatment with an acid reagent which follows this treatment with analkali metal hydroxide may also be carried out in the same manner as thetreatment with an acid reagent which has been described with referenceto (Process i) and (Process ii).

In the above (Process iii), the cyclopropanecarboxylic acid derivativeconsisting of a cyclopropanecarboxylic acid of general formula (IX) andits ester of general formula (IV) and the γ-lactone derivative ofgeneral formula (I) are treated with an alcohol (II) under heating andin the presence of an acid catalyst. This treatment causes thecarboxylic acid of general formula (IX) to undergo esterification withthe alcohol used to yield the corresponding carboxylic acid ester inhigh yield. The carboxylic acid ester (IV) applied to this treatmentstage, where the alcohol used in this treatment is an alcohol notcorresponding to the alcohol residue of said ester, is converted to thecarboxylic acid ester whose alcohol residue corresponds to the alcoholused in the treatment as said treatment causes a part or all of thesupplied ester to undergo esterification. Preferred examples of thealcohol are lower alcohols such as methanol, ethanol, propanol, butanol,etc., although other alcohols within the ambit of general formula (II)may also be employed. The acid catalyst may be one of the acid catalystswhich are normally used as catalysts for esterification reactions,particularly desirable catalysts including formic acid, propionic acid,isobutyric acid, cyclohexanecarboxylic acid, adipic acid, benzoic acid,phenol, cresol, hydroquinone, p-toluenesulfonic acid, benzenesulfonicacid, sulfuric acid, hydrochloric acid, phosphoric acid, boric acid andso forth. The amount of acid catalyst is desirably about 0.01 to 10weight percent based on the weight of the cyclopropanecarboxylic acidderivative obtained upon treatment with an alkali metal hydroxide. It isto be understood that the γ-lactone derivative of general formula (I) isnot modified at all in the above treatment. From the resultant mixturecontaining the ester (IV) of carboxylic acid (IX) and the γ-lactonederivative of general formula (I), the two compounds are independentlyseparated. This separation may be easily accomplished by distillation.

In this (Process iii), the above byproduct γ-lactone derivative (I) isfurther reacted with a hydrogen halide and an alcohol (II) to obtain thecorresponding ester of general formula (III). This reaction is carriedout after the γ-lactone derivative (I) is separated from the above ester(IV) of cyclopropanecarboxylic acid (IX), by permitting a hydrogenhalide and an alcohol (II) to act upon the γ-lactone derivative thusseparated. Following this reaction, if there are residues of hydrogenhalide and/or alcohol, these residues are separated by distillation andrecovered. The distillation residue is further distilled under reducedpressure to obtain the ester of general formula (III).

The ester of general formula (III) obtained from the byproduct γ-lactonederivative (I) in the above manner is treated with an alkali metalhydroxide and, then, with an acid reagent to obtain a mixture of acyclopropanecarboxylic acid derivative consisting of acyclopropanecarboxylic acid of general formula (IX) and an ester thereof(IV) and a γ-lactone derivative (I). This mixture is heated togetherwith an alcohol (II) in the presence of an acid catalyst and thecyclopropanecarboxylic acid ester (IV) is then separated and recovered.The above treatment with an alkali metal hydroxide, the treatment withan acid reagent and the treatment with an alcohol under heating in thepresence of an acid catalyst may also be carried out in the same mannersas the treatment of starting material ester with an alkali metalhydroxide, treatment with an acid reagent and subsequent treatment byheating with an alcohol in the presence of an acid catalyst,respectively, which have been described hereinbefore.

Only for the purpose of assisting in a better understanding of (Processiii), a few modes of embodiment will be schematically shown below. Inthe following formulas, Me, Et and TosOH stand for methyl, ethyl andp-toluenesulfonic acid, respectively. ##STR14## It should be understoodthat, in the above (Process i), instead of separating and recovering thecyclopropanecarboxylic acid ester (IV) from the reaction mixturefollowing the treatment of a mixture of γ-lactone derivative (I) andcyclopropanecarboxylic acid derivative with hydrogen halide and alcohol(II), said reaction mixture may be directly subjected to said treatmentwith a basic reagent. Moreover, referring to the above (Process iii),instead of separating and recovering the cyclopropanecarboxylic acidester (IV) from the reaction mixture following the treatment of amixture of γ-lactone derivative and cyclopropanecarboxylic acidderivative by heating with alcohol (II) in the presence of an acidcatalyst, said reaction mixture may be directly reacted with hydrogenhalide and alcohol (II).

It should also be understood that the treatments according to (Processi), (Process ii) and (Process iii) may be carried out independently ofthe processing steps hereinbefore described but when the above (Processi), (Process ii) and (Process iii) are carried out in repetition orcontinuously, it is desirable to recycle the ester (III) obtained fromthe by-produced or concomitantly produced γ-lactone derivative (I) as aportion of starting material to the stage in which the treatment ofstarting ester with a basic reagent is performed. In this manner, thenecessary initial amount of starting material ester can be considerablyreduced. The foregoing method not only enables one to convert thebyproduced or concomitantly produced γ-lactone derivatives to usefulcompounds and thereby to obtain the cyclopropanecarboxylic acidderivatives in good yield but also has the advantage that therestrictions on the conditions of said ring-closing reaction areconsiderably alleviated.

The following examples are further illustrative of the presentinvention. In these examples, all parts are by weight and, unlessotherwise specified, all NMR data are those obtained in carbontetrachloride with tetramethylsilane as the internal reference at roomtemperature and 60 MHz.

EXAMPLE 1

To 80 parts of a methanolic solution of hydrogen chloride (concentrationof hydrogen chloride: about 47%) was added 100 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (in general formula(I), X, Y=Cl; R¹, R² =CH₃ ; R³ =H) and the mixture was stirred at roomtemperature for 12 hours. The reaction mixture was directly distilled torecover the excess hydrogen chloride and methanol and further distilledunder reduced pressure. By the above procedure was obtained 116 parts ofmethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (yield 94%), theproperties of which are given below.

bp: 80°-82° C./0.3 mmHg

NMR spectrum (δ): 1.15 (s) 6H, 2.22 (d, J=14 Hz) 1H, 2.55 (d, J=15 Hz)1H, 3.68 (s) 3H, 4.93 (d, J=11 Hz) 1 H, 6.10 (d, J=11 Hz) 1 H

IR spectrum (liquid film): 1615 cm⁻¹ (C=C), 1735 cm⁻¹ (CO)

EXAMPLE 2

To 100 parts of an ethanolic solution of hydrogen chloride(concentration of hydrogen chloride: about 45%) was added 100 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide and the mixture wasstirred at room temperature for 18 hours. Thereafter, the reactionmixture was treated in the same manner as Example 1. By this procedurewas obtained 120 parts of ethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate(yield 92%), the properties of which are given below.

bp: 91°-92° C./0.4 mmHg

IR spectrum (liquid film): 1610 cm⁻¹ (C═C), 1730 cm⁻¹ (CO)

NMR spectrum (100 MHz) δ: 1.08 (s) 6H, 1.20 (t, J=7 Hz) 3H, 2.14 (d,J=14 Hz) 1H, 2.42 (d, J=14 Hz) 1H, 4.01 (q, J=7 Hz) 2 H, 4.83 (d, J=11Hz) 1H, 5.95 (d, J=11 Hz) 1H

Elemental analysis (Calcd. values in parentheses): C, 43.77(43.90)%; H,5.47 (5.53)%

EXAMPLE 3

Under cooling with ice, hyrogen chloride gas was bubbled into a mixtureof 50 parts of 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide and 100parts of methanol. After it was confirmed by gas chromatography that thereaction had gone to completion, the reaction mixture was treated in thesame manner as Example 1. By the above procedure was obtained 56 partsof methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (yield 90%). Thisproduct was shown to have properties identical with those of the esterobtained in Example 1.

EXAMPLE 4

To 30 parts of methanol saturated with hydrogen chloride gas(concentration of hydrogen chloride: about 50%) was added 41.8 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide, followed by heatingin a closed tubular reactor at 70°-80° C. for 3 hours. The reactionmixture was then treated in the same manner as Example 1. By the aboveprocedure was obtained 49.8 parts of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate (yield 96%). This product wasfound to have properties identical with those of the product accordingto Example 1.

EXAMPLE 5

The procedure of Example 2 was repeated except that 107 parts of2,3,3-trimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (in general formula(I), X, Y=Cl; R¹, R², R³ =CH₃) was used in lieu of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide. By the aboveprocedure was obtained 32 parts of ethyl2,3,3-trimethyl-4,6,6-trichloro-5-hexenoate which had the propertiesgiven below. The yield was 92% based on the reacted2,3,3-trimethyl-4-(2',2'-dichlorovinyl)-4-butanolide.

bp: 104°-106° C./0.4 mmHg

IR spectrum (liquid film): 1610 cm⁻¹ (C=C), 1730 cm⁻¹ (CO) NMR spectrum(100 MHz)δ: 1.20 (t, j=9 Hz), 0.9-1.3, 12 H; 2.4-2.7 (m) 1H; 4.01 (q,J=7 Hz), 4.03 (q, J=7 Hz) 2H; 4.63 (d, J=11 Hz), 4.78 (d, J=11 Hz) 1H;5.96 (d, J=11 Hz), 5.97 (d, J=11 Hz) 1H

Elemental analysis (Calcd. values in parentheses): C, 46.20 (45.94)% H;6.02 (5.96)%

EXAMPLE 6

Under cooling with ice, hydrogen bromide gas was bubbled into a mixtureof 29.8 parts of 3,3-dimethyl-4-(2',2'-dibromovinyl)-4-butanolide and100 parts of ethanol. After it was confirmed by gas chromatography thatthe reaction had gone to completion, the reaction mixture was treated inthe same manner as Example 1. By the above procedure was obtained 33.3parts of ethyl 3,3-dimethyl-4,6,6-tribromo-5-hexenoate (yield 82%) whichwas shown to have the following properties.

IR spectrum (liquid film): 1600 cm⁻¹ (C═C), 1730 cm⁻¹ (CO)

NMR spectrum δ: 1.12 (s) 6H, 1.22 (t, J=7 Hz) 3H, 2.17 (d=15 Hz) 1 H,2.49 (d, J=15 Hz) 1H, 4.08 (q, J=7 Hz) 2H, 4.93 (d, J=11 Hz) 1H, 6.66(d, J=11 Hz) 1H

EXAMPLES 7-9

In 30 parts of diethyl ether was dissolved 4.2 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide and, as shown in Table1, n-octyl alcohol, 3-phenoxybenzyl alcohol or allethrolone was added tothe above solution. Then, at room temperature, hydrogen chloride gas wasbubbled into the solution for 2 hours. The, low-boiling fractions weredistilled off and the residue was chromatographed on a silica gel columnto isolate the contemplated product. The results are set forth in Table1.

                                      TABLE 1                                     __________________________________________________________________________                        Product,        NMR spectrum of                           Example                                                                            Alcohol, parts parts (% yield) product, δ                          __________________________________________________________________________    7    n-Octyl alcohol [n-C.sub.8 H.sub.17 OH] 13                                                    ##STR15##      0.85 (t, J = 6Hz) 3H, 1.08 (s) 6H,                                            1.29(bs) 12H, 2.16 (d, J = 15Hz) 1H,                                          2.49 (d, J = 15Hz) 1H, 4.02(d, J =                                            6Hz) 2H, 4.90(d, J = 11Hz) 1H,                                                6.07(d, J = 11Hz) 1H                        8                                                                                 ##STR16##                                                                                    ##STR17##      1.03 (s) 6H, 2.18 (d, J =  15Hz) 1H,                                          2.52 (d, J = 15Hz) 1H, 4.87 (d, J =                                           11Hz) 1H, 5.02 (s) 2H, 6.02 (d, J =                                           11Hz) 1H, 6.80- 7.50 (m) 9H                 9                                                                                 ##STR18##                                                                                    ##STR19##      1.12 (s) 6H, 1.98 (bs) 3H, 2.13-3.08                                          (m) 6H, 4.72-6.50 (m)                     __________________________________________________________________________                                        6H                                    

EXAMPLE 10

In 30 parts of methanol was dissolved 6.0 parts of sodium hydroxide.Separately, a mixture of 26.0 parts of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate and 13 parts of methanol wasprepared. The methanolic solution of sodium hydroxide was added dropwiseto the latter mixture under reflux over a period of 30 minutes, followedby stirring at that temperature for 30 minutes. Thereafter, the reactionmixture was allowed to cool and neutralized with concentratedhydrochloric acid. The methanol was distilled off under reduced pressureto recover a mixture of oily product and solid sodium chloride. Thesolid was dissolved by the addition of water, followed by extraction wihdiethyl ether. The ether layer was dried over anhydrous magnesiumsulfate and the ether was distilled off. By the above procedure wasobtained 22.5 parts of a mixture of2,2-dimethyl-3-(2',2'-dichlorovinyl)-cyclopropanecarboxylic acid, methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate and3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide. To this mixture wasadded 25 parts of methanol in which hydrogen chloride gas had beenabsorbed (concentration of hydrogen chloride: about 50%), followed bystirring at room temperature overnight. Then, the excess hydrogenchloride and methanol were distilled off under reduced pressure,whereupon 24.4 parts of oily product was obtained as the residue. Gaschromatographic analysis revealed that this product was a mixture of15.9 parts of methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate (yield 71%, cis/trans ratio=24:76) and 7.0 partsof methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (27% based onstarting material). This mixture was then distilled under reducedpressure to recover 14.2 parts of methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate (bp:67°-69° C./0.2 mmHg, NMR (δ):1.12-1.25 (m) 6H, 1.42-2.25 (m) 2H, 3.60(s) 3H, 5.57 (d, J=8.5 Hz), 6.23 (d, J=8.5 Hz) 1H) and 5.9 parts ofmethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (bp: 80°-82° C./0.3mmHg; NMR (δ): 1.15 (s) 6H, 2.22 (d, J=15 Hz) 1H, 2.55 (d, J=15 Hz) 1H,3.68 (s) 3H, 4,93 (d, J=11 Hz) 1H, 6.10 (d, J=11 Hz) 1 H; IR (liquidfilm) 1615 cm⁻¹ (C═C), 1735 cm⁻¹ (CO)).

To 5.9 parts of the above methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate was added a sufficient amountof fresh methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate to make a totalof 26.0 parts and exactly the same procedure as above was repeated.After distillation, there were obtained 14.0 parts of methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate and 6.1parts of methyl 3,3-dimethyl-4,6,6-trichloro b 5-hexenoate. By repeatingthis recycle of byproduct methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate to fresh starting material,there was obtained methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate in a yield of 97% based on starting methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate.

EXAMPLE 11

In 100 parts of methanol was dissolved 5.5 parts of sodium metal and,while the reaction temperature was maintained at 40°-50° C., 51.9 partsof methyl 3,3-dimethyl-4,6,6-trichloro-5-hexonoate was added dropwise tothe above solution over a period of about an hour. The mixture was thenstirred at room temperature for about 1.5 hours. The reaction mixturewas allowed to cool and neutralized with a methanolic solution ofhydrogen chloride. The methanol was then distilled off under reducedpressure. By the above procedure was obtained a mixture of oily productand solid sodium chloride. The solid was dissolved by the addition ofwater, followed by extraction with diethyl ether. The ether layer wasdried over anhydrous magnesium sulfate and the ether was then distilledoff. The procedure provided 45.1 parts of an oily product. This productwas subjected to distillation under reduced pressure. The distillationprocedure yielded, as a first cut, 40.2 parts of methyl2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate (yield 90%;cis/trans ratio=25:75; bp: 67°- 69° C. /0.2 mmHg) and, then, 2.1 partsof 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 5% bp:94°-97° C./0.4 mmHg; NMR (δ):1.01 (s) 3H, 1.19 (s) 3H, 2.13 (d, J=17 Hz)1H, 2.43 (d,J=17 Hz) 1H, 4.78 (d, J=9 Hz) 1H, 5.95 (d, J=9 Hz) 1H; IR(liquid film): 1620 cm⁻¹ (C═C), 1785 cm⁻¹ (CO)). To 2.1 parts of thelatter distillate 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide wasadded 2 parts of a methanolic solution of hydrogen chloride(concentration of hydrogen chloride: about 50%) and the mixture wasstirred at room temperature overnight. The excess hydrogen chloride andmethanol were distilled off under reduced pressure and the resultantresidue was distilled under reduced pressure. The procedure provided 2.5parts of methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (yield 96%based on 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide; bp: 80°-82°C./0.3 mmHg).

To the methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate thus obtained(2.5 parts) was added a sufficient amount of fresh methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate to make a total of 51.9 partsand the mixture was subjected to exactly the same procedure as describedabove. After the distillation stage, there was obtained 40.6 parts ofmethyl 2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate. The3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (2.0 parts)concomitantly produced in the above procedure was treated with amethanolic solution of hydrogen chloride. By the above procedure wasobtained 2.5 parts of methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate.

Thus, by repeating the procedure of converting the3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide to methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate and recycling the lattercompound as an additional amount of starting material, methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate wasobtained in an overall yield of 95% (based on methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate).

EXAMPLE 12

In 100 parts of methanol was dissolved 16.0 parts of sodium hydroxide.Separately, a mixture of 31.0 parts of ethyl3,3-dimethyl-4,6,6,6-tetrachlorohexanoate and 30 parts of methanol wasprepared. The above methanolic solution of sodium hydroxide was addeddropwise under reflux to said mixture over a period of 30 minutes,followed by stirring at that temperature for 30 minutes. The reactionmixture was allowed to cool and neutralized with concentratedhydrochloric acid. The methanol was then distilled off under reducedpressure to recover a mixture of oily product and solid sodium chloride.The solid was dissolved by the addition of water, followed by extractionwith diethyl ether. The ether layer was dried over anhydrous magnesiumsulfate and the ether was distilled off. By the above procedure wasobtained 21.4 parts of a mixture of methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate,2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylic acid and3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide.

To the above mixture was added 20 parts of a methanolic solution ofhydrogen chloride gas (concentration of hydrogen chloride: about 50%),followed by stirring at room temperature overnight. Thereafter, theexcess hydrogen chloride and methanol were distilled off under reducedpressure, whereupon 22.5 parts of oily product was obtained as aresidue. Gas chromatographic analysis showed that this residue was amixture of 9.4 parts of methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate (yield 42% cis/trans ratio=25:75) and 12.7 partsof methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (yield 49%).

This mixture was subjected to distillation under reduced pressure toseparate 8.5 parts of methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate (bp: 67°-69° C./0.2 mmHg) and 11.8 parts ofmethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (bp: 80°-82° C./0.3mmHg). The latter compound methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate was then treated in exactly thesame manner as Example 10. In this manner, methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate wasobtained in a yield of 97%.

EXAMPLE 13

In 200 parts of ethanol was dissolved 10.4 parts of sodium metal and, ata constant temperature of 55°-60° C., 46.6 parts of ethyl3,3-dimethyl-4,6,6,6-tetrachlorohexanoate was added to the abovesolution dropwise over a period of 1 hour. The mixture was then stirredat the same temperature for 2 hours. The reaction mixture was thenallowed to cool and neutralized with an ethanolic solution of hydrogenchloride. The ethanol was distilled off under reduced pressure to obtaina mixture of oily product and solid sodium chloride. The solid wasdissolved by the addition of water, followed by extraction with diethylether. The ether layer was dried over anhydrous magnesium sulfate andthe ether was distilled off. By the above procedure was obtained 36.5parts of oily product.

This product was further subjected to distillation under reducedpressure to separate 25.5 parts of ethyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate (yield 72%,cis/trans ratio=29:71, bp: 72°-74° C./0.4 mmHg; NMR (100 MHz)δ:1.12-1.40(m) 9H; 1.45-2.30 (m) 2H; 4.12 (q, J=7 Hz) 2H; 5.63 (d, J=8 Hz), 6.29(d, J=8 Hz) 1H) and 3.0 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 10%, bp:94°-97° C./0.4 mmHg).

To this latter compound3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (3.0 parts) was added3.5 parts of an ethanolic solution of hydrogen chloride (concentrationof hydrogen chloride: about 45%) and the mixture was stirred at roomtemperature overnight. Then, the excess hydrogen chloride and ethanolwere distilled off under reduced pressure and the residue was furtherdistilled under reduced pressure. By this procedure was obtained 3.6parts of ethyl 3,3-dimethyl-4,6,6-trichloro-5-hexanoate (yield 92% basedon 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide; bp: 91°-92° C./0.4mmHg; NMR (100 MHz) : 1.08(s)6H, 1.20 (t,J=7 Hz)3H, 2.14(d,J=14 Hz)1H,2.42(d,J=14 Hz)1H, 4.01(q,J=7 Hz) 2H, 4.83 (d, J=11 Hz) 1H, 5.95 (d,J=11 Hz) 1H).

The ethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenote (3.6 parts) obtainedas above was added to 42.4 parts of starting material ethyl3,3-dimethyl-4,6,6,6-tetrachlorohexanoate and the resultant mixture(mole ratio=1:10) was subjected to exactly the same procedure asdescribed above. Following the distillation stage, there was obtained25.7 parts of ethyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate (yield 72%; cis/trans ratio=29:71; bp: 72°-75°C./0.4 mmHg). The 3,3-dimethyl-4-(2,2-dichlorovinyl)-4-butanolideconcomitantly produced in the above procedure was treated with hydrogenchloride and ethanol, whereby 3.4 parts of ethyl3,3-dimethyl-4,6,6-trichloro-5-hexanoate was obtained. By repeating theprocedure of converting the byproduct3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide to ethyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate and recycling the lattercompound as starting material, there was obtained ethyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate in anoverall yield of 78%.

EXAMPLE 14

The procedure of Example 10 was repeated except that a mixture of 14.8parts of methyl 3,3-dimethyl-4,6,6,6-tetrachlorohexanoate and 12.9 partsof methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (mole ratio=1:1) wasused in lieu of methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate. By theabove procedure was obtained 23.0 parts of a mixture of2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylic acid, methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate and3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide. This mixture wastreated with a methanolic solution of hydrogen chloride (concentrationof hydrogen chloride: about 50%) to obtain 23.8 parts of oily product.Gas chromatographic analysis showed that this product was a mixture of13.8 parts of methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate (yield 62% based on starting material; cis/transratio=25:75) and 8.8 parts of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate (34% based on startingmixture). This mixture was then subjected to distillation under reducedpressure to obtain 12.5 parts of contemplated compound methyl2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate, followed byrecovery of 8.0 parts of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate.

To the above methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (8.0 parts)was added 14.8 parts of methyl3,3-dimethyl-4,6,6,6-tetrachlorohexenoate, together with 4.9 parts ofmethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate to make a total of 27.7parts and the mixture was subjected to exactly the same procedure asdescribed above. Following the distillation stage, 12.8 parts of methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate and 8.2parts of methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate were obtained.By repeating the procedure of recycling the methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate thus concomitantly produced asa starting material, there was obtained methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate in anoverall yield of 94%.

EXAMPLE 15

The procedure of Example 11 was repeated except that a mixture of 26.0parts of methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate and 26.0 partsof methyl 3,3-dimethyl-6,6,6-trichloro-4-hexenoate (mole ratio=1:1) wasused in lieu of methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate toobtain 37.9 parts of methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate (yield 85% based on starting material; cis/transratio=29:71) and 4.6 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 11% based onstarting material). The latter compound3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (4.6 parts) wastreated with 5.0 parts of a methanolic solution of hydrogen chloride(concentration of hydrogen chloride: about 50%) to obtain 5.5 parts ofmethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (yield 96% based on3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide).

To this methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (5.5 parts) wasadded 26.0 parts of methyl 3,3-dimethyl-6,6,6-trichloro-4-hexenoatetogether with 20.5 parts of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate to make a total of 52.0 partsand the mixture was subjected to exactly the same procedure as above.Following the distillation stage, there was obtained 36.8 parts ofmethyl 2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylatealong with 5.8 parts of methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate.By repeating the procedure of converting the3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide thus concomitantlyproduced to methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate andrecycling the latter as a starting material, there was obtained methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate in anoverall yield of 95%.

EXAMPLE 16

In 80 parts of methanol was dissolved 12.0 parts of sodium hydroxideand, at the reflux temperature of methanol, 51.9 parts of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate was added dropwise to the abovesolution over a period of 30 minutes, followed by stirring the mixtureat that temperature for 30 minutes. Then, about 50 parts of water wasadded and, after refluxing for about 30 minutes, the reaction mixturewas allowed to cool and neutralized with concentrated hydrochloric acid.The methanol was distilled off under reduced pressure and the residuewas extracted with diethyl ether. The ether layer was dried and theether was distilled off, whereupon 42.2 parts of a mixture of2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylic acid and3,3-dimethyl-4-(2',2'-dichloroviyl)-4-butanolide. This mixture wasfurther distilled under reduced pressure to separate 10.4 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 25%; bp:86°-91° C./0.2 mmHg) and 22.3 parts of2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylic acid (yield53%; bp: 105°-108° C./0.2 mmHg). Then, 10.4 parts of the former product3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide was dissolved in 70parts of methanol and, under cooling with ice, hydrogen chloride gas wasbubbled into the solution for about 1.5 hours. Thereafter, the excesshydrogen chloride and methanol were distilled off under reduced pressureand the residue was further subjected to distillation under reducedpressure. By this procedure was obtained 12.1 parts of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate (yield 23% based on startingmaterial).

The methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate obtained as abovewas added to a fresh charge of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate and the starting materialmixture was subjected to exactly the same procedure as described aboveto produce 2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylicacid. By repeating the procedure of converting the3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide concomitantly obtainedto methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate and recycling andadding the latter to a fresh charge of starting material, there wasobtained 2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylicacid in an overall yield of 70% based on the methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate employed.

EXAMPLE 17

In 50 parts of ethanol was dissolved 2.8 parts of sodium metal.Separately, a mixture of 28.8 parts of ethyl2,3,3-trimethyl-4,6,6-trichloro-5-hexenoate and 20 parts of ethanol wasprepared. The ethanolic solution of sodium metal was then added dropwiseto this mixture at a constant temperature of 50°-60° C. over a period of1 hour, followed by stirring at that temperature for 2 hours.Thereafter, the reaction mixture was neutralized and extracted withether as in Example 11. By this procedure was obtained 25.8 parts ofoily product. Column chromatography was carried out on this product(silica gel; elute=n-hexane-benzene (1:1)) to recover 20.0 parts ofethyl 1,2,2-trimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate(yield 80%; NMR, δ: 1.04 (s), 1.13 (s), 1.18 (s), 1.23 (t, J=7 Hz) 12 H;2.25 (d, J=8 Hz) 1 H; 4.08 (q, J=7 Hz) 2 H; 5.57 (d, J=8 Hz), 6.30 (d,J=8 Hz) 1 H) and 2.9 parts of2,3,3-trimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 13%; NMR, δ:0.78-1.17 (m) 9 H; 2.07-2.53 (m) 1 H; 4.71 (d, J=9 Hz), 4.74 (d, J=9 Hz)1 H; 5.93 (d, J=9 Hz), 5.99 (d, J=9 Hz) 1H; m p: 58° C.

Then, by a procedure similar to that described in Example 13 the latterproduct 2,3,3-trimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (2.9 parts)was treated with 8 parts of an ethanolic solution of hydrogen chloride(concentration of hydrogen chloride: about 45%) to obtain 3.4 parts ofethyl 2,3,3-trimethyl-4,6,6-trichloro-5-hexenoate (b p: 104°-106° C./0.4mmHg; NMR (100 MHz)δ:1.20 (t, J=9 Hz), 0.9-1.3, 12 H; 2.4-2.7 (m) 1 H;4.01 (q, J=7 Hz), 4.03 (q, J=7 Hz) 2 H; 4.63 (d, J=11 Hz), 4.78 (d, J=11Hz) 1 H; 5.96 (d, J=11 Hz), 5.97 (d, J=11 Hz) 1 H; IR (liquid film):1610 cm⁻¹ (C═O), 1730 cm⁻¹ (CO)). This compound was recycled and addedto a fresh charge of starting material ethyl2,3,3-trimethyl-4,6,6-trichloro-5-hexenoate and the mixture wassubjected to exactly the same procedure as described above to obtainethyl 1,2,2-trimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate. Byrepeating the procedure of converting the2,3,3-trimethyl-4-(2',2'-dichlorovinyl)-4-butanolide concomitantlyobtained to ethyl 2,3,3-trimethyl-4,6,6-trichloro-5-hexenoate andrecycling it as a starting material, there was obtained ethyl1,2,2-trimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate in anoverall yield of 90% based on ethyl2,3,3-trimethyl-4,6,6-trichloro-5-hexenoate.

EXAMPLE 18

The procedure of Example 10 was repeated except that 40.7 parts of ethyl3,3-dimethyl-4,6,6-tribromo-5-hexenoate was used in lieu of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate. Thus, the starting materialwas first treated with a methanolic solution of 6.0 parts of sodiumhydroxide to obtain 31.0 parts of a mixture of2,2-dimethyl-3-(2',2'-dibromovinyl) cyclopropanecarboxylic acid,3,3-dimethyl-4-(2',2'-dibromovinyl)-4-butanolide and methyl2,2-dimethyl-3-(2',2'-dibromovinyl) cyclopropanecarboxylate.

This mixture was treated with 40 parts of an ethanolic solution ofhydrogen chloride (concentration of hydrogen chloride: about 45%) toobtain 15.3 parts of ethyl 2,2-dimethy- -3-(2',2'-dibromovinyl)clopropanecarboxylate (yield 47%; NMR (100 MHz)δ:1.19 (s), 1.23 (t, J=7Hz), 1.26 (s) 9 H; 1.53 (d, J=5 Hz) 1 H; 2.08 (dd, J=5 & 8 Hz) 1 H; 4.03(q, J=7 Hz) 2 H; 6.04 (d, J=8 Hz) 1 H; IR (liquid film): 1600 cm⁻¹(C═C), 1730 cm⁻¹ (CO)) and 15.2 parts of ethyl3,3-dimethyl-4-chloro-6,6-dibromo-5-hexenoate (yield 42%).

Then, the latter compound ethyl3,3-dimethyl-4-chloro-6,6-dibromo-5-hexenoate (15.2 parts) was added to23.6 parts of starting material ethyl3,3-dimethyl-4,6,6-tribromo-5-hexenoate and the mixture was subjected toexactly the same procedure as described above. Following thedistillation stage, 15.0 parts of ethyl2,2-dimethyl-3-(2',2'-dibromovinyl) cyclopropanecarboxylate and 15.5parts of ethyl 3,3-dimethyl-4-chloro-6,6-dibromo-5-hexenoate wereobtained. By repeating the procedure of recycling the ethyl3,3-dimethyl-4-chloro-6,6-dibromo-5-hexenoate concomitantly produced asa starting material, there was obtained ethyl2,2-dimethyl-3-(2',2'-dibromovinyl) cyclopropanecarboxylate in anoverall yield of 81%.

EXAMPLE 19

In 50 parts of methanol was dissolved 6.0 parts of sodium hydroxide.Separately, a mixture of 26.0 parts of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate and 13 parts of methanol wasprepared. The methanolic solution of sodium hydroxide was added dropwiseunder reflux to this mixture over a period of 30 minutes, followed bystirring at that temperature over a period of 30 minutes. The reactionmixture was allowed to cool and neutralized with concentratedhydrochloric acid. The methanol was then distilled off under reducedpressure, whereupon a mixture of oily product and solid sodium chloridewas obtained. The solid was dissolved by the addition of water and,then, extracted with diethyl ether. The ether layer was dried overanhydrous magnesium sulfate and the ether was distilled off. The aboveprocedure provided 22.5 parts of a mixture of2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylic acid, methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate and3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide. Then, 100 parts ofmethanol and 0.1 part of p-toluenesulfonic acid were added to the abovemixture, followed by heating under reflux for 20 hours. Thereafter, themethanol was distilled off under reduced pressure, whereupon 21.5 partsof oily product was obtained as a residue. Gas chromatographic analysisshowed that it was a mixture of 15.4 parts of methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate (yield 69%;cis/trans ratio=24:76) and 5.4 parts of 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 26%). This mixture wassubjected to distillation under reduced pressure to obtain 13.9 parts ofmethyl 2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate (bp: 67°-69° C./0.2 mmHg; NMR, δ:1.12-1.25 (m) 6 H; 1.42-2.25 (m) 2 H;3.60 (s) 3 H; 5.57 (d, J=8.5 Hz), 6.23 (d, J=8.5 Hz)1 H) and 4.7 partsof 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (b p: 94°-97°C./0.4 mmHg; NMR, δ:1.01 (s) 3 H, 1.19 (s) 3 H, 2.13 (d, J=17 Hz) 1 H,2.43 (d, J=17 Hz) 1 H, 4.78 (d, J=9 Hz) 1 H, 5.95 (d, J=9 Hz) 1 H; IR(liquid film): 1620 cm⁻¹ (C═C), 1785 cm⁻¹ (CO).

Then, 5 parts of a methanolic solution of hydrogen chloride(concentration of hydrogen chloride: about 50%) was added to 4.7 partsof the latter compound3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide, followed by stirringat room temperature overnight. The excess hydrogen chloride and methanolwere distilled off under reduced pressure and the residue was furtherdistilled under reduced pressure to obtain 5.6 parts of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate (bp: 80°-82° C./0.3 mmHg; NMR,δ:1.15 (s) 6 H, 2.22 (d, J=15 Hz) 1 H, 2.55 (d, J=15 Hz) 1 H, 3.68 (s) 3H, 4.93 (d, J=11 Hz) 1 H, 6.10 (d, J=11 Hz) 1 H; IR (liquid film): 1615cm⁻¹ (C═C), 1735⁻¹ (CO); yield 96% based on3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide).

To 5.6 parts of the methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoateobtained as above was added a sufficient amount of fresh methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate to make a total of 26.0 partsand exactly the same procedure as set forth above was repeated.Following the distillation stage, 14.2 parts of methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate wasobtained. The 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolideconcomitantly produced in the above procedure (4.9 parts) was treatedwith a methanolic solution of hydrogen chloride to obtain 5.8 parts ofmethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate.

By repeating the above procedure of converting the3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide to methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate and recycling and adding thelatter to starting material on the one hand, and by the procedure ofcollecting an intermediate distillate between the methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate and3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide fractions, whichcomprises a mixture of these two compounds, and subjecting thisintermediate distillate to distillation under reduced pressure toseparate and recover methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate on the other hand, there was obtained methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate in anoverall yield of about 90% based on the methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate employed.

EXAMPLE 20

In 100 parts of methanol was dissolved 16.0 parts of sodium hydroxide.Separately, a mixture of 31.0 parts of ethyl3,3-dimethyl-4,6,6,6-tetrachlorohexanoate and 30 parts of methanol wasprepared. The above methanolic solution of sodium hydroxide was addeddropwise to the above mixed solution at the reflux temperature over aperiod of 30 minutes, followed by stirring at that temperature for 30minutes. Then, the reaction mixture was allowed to cool and neutralizedwith concentrated hydrochloric acid. The methanol was then distilled offunder reduced pressure to recover a mixture of oily product and solidsodium chloride. The solid was dissolved by the addition of water,followed by extraction with diethyl ether. The ether layer was driedover anhydrous magnesium sulfate and the ether was distilled off. By theabove procedure was obtained 21.4 parts of a mixture of2,2-dimethyl-3-(-b 2-40 ,2'-dichlorovinyl)-cyclopropanecarboxylic acid,methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate and3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide.

To the above mixture was added 100 parts of methanol together with 0.1part of p-toluenesulfonic acid and the entire mixture was refluxed for20 hours. The reaction mixture was subjected to distillation underreduced pressure to remove the methanol, whereupon 21.5 parts of oilyproduct was obtained as a residue. Gas chromatographic analysis of theresidue revealed that it was a mixture of 9.8 parts of methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate (yield 44%;cis/trans ratio=25:75) and 10.4 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 50%). Thismixture was subjected to distillation under reduced pressure to obtain8.8 parts of methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate (bp: 67°-69° C./0.2 mmHg) and 9.0 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (bp: 94°-97° C./0.4mmHg).

To the latter product 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide(9.0 parts) was added 10 parts of a methanolic solution of hydrogenchloride (concentration of hydrogen chloride: about 45%) and the mixturewas stirred at room temperature overnight. The excess hydrogen chlorideand methanol were distilled off under reduced pressure and the residuewas further subjected to distillation under reduced pressure. By theabove procedure was obtained 10.8 parts of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate (bp: 80°-82° C./0.3 mmHg; yield97% based on the 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide).

The above methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate was treated inthe same manner as Example 19, whereby methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate wasobtained in a yield of about 90%.

EXAMPLE 21

The procedure of Example 20 was repeated except that a mixture of 13.7parts of ethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate and 15.5 partsof ethyl 3,3-dimethyl-4,6,6,6-tetrachlorohexanoate was used in lieu of31.0 parts of ethyl 3,3-dimethyl-4,6,6,6-tetrachlorohexanoate. In thefirst place, 29.2 parts of the above mixture was treated with 16.0 partsof sodium hydroxide in solvent methanol to obtain 22.1 parts of amixture of 2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylicacid, methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate and3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide.

This mixture was treated with 0.1 part of p-toluenesulfonic acid and 100parts of ethanol under heating and, then, the ethanol was distilled off.Gas chromatographic analysis showed that the residue was a mixture of14.2 parts of ethyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate (yield 60% cis/trans ratio=25:75) and 7.3 partsof 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 35%). Thismixture was then subjected to distillation under reduced pressure torecover 13.3 parts of ethyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate (bp: 72°-74° C./0.4 mmHg; NMR (100 MHz)δ:1.12-1.40 (m) 9 H, 1.45-2.30 (m) 2H, 4.12 (q, J=7 Hz) 2 H, 5.63 (d, J=8Hz), 6.29 (d, J=8 Hz) 1H) and 6.5 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (bp: 94-97° C./0.4mmHg).

The latter compound 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide(6.5 parts) was treated with 8 parts of an ethanolic solution ofhydrogen chloride (concentration of hydrogen chloride: about 45%) toobtain 8.2 parts of ethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (b p:91°-92° C./0.4 mmHg; NMR (100 MHz)δ: 1.08 (s) 6 H, 1.20 (t, J=7 Hz) 3 H,2.14 (d, J=14 Hz) 1 H, 2.42 (d, J=14 Hz) 1 H, 4.01 (q, J=7 Hz) 2 H, 4.83(d, J=11 Hz) 1 H, 5.95 (d, J=11 Hz) 1 H; yield 96% based on3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide).

To the above ethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (8.2 parts)was added 5.5 parts of ethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoatetogether with 15.5 parts of ethyl3,3-dimethyl-4,6,6,6-tetrachlorohexanoate. With this mixture as astarting material, the procedure described above was repeated. Afterdistillation under reduced pressure; there was obtained 13.7 parts ofethyl 2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate. The3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (6.3 parts)concomitantly produced in the above procedure was treated with anethanolic solution of hydrogen chloride to obtain 7.9 parts of ethyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate.

By repeating the above procedure of converting the3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide to ethyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate and recycling the lattercompound on the one hand, and by the procedure of collecting anintermediate distillate between the ethyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate and3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide fractions, whichcomprised a mixture of these two compounds, and subjecting saidintermediate distillate to distillation under reduced pressure toseparate ethyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate on the other hand, there was obtained ethyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate in anoverall yield of about 90% based on the starting material mixture.

EXAMPLE 22

The procedure of Example 19 was repeated exept that 16.8 parts ofpotassium hydroxide was used in lieu of 6.0 parts of sodiuim hydroxideand that a mixture of 44.1 parts of methyl3,3-dimethyl-4,6,6-trichloro-b 5-hexenoate and 7.8 parts of methyl 3,3-dimethyl-6,6,6-trichloro-4-hexenoate was used in lieu of 26.0 parts ofmethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate. First, 51.9 parts ofthe above mixture was treated with 16.8 parts of potassium hydroxide in200 parts of methanol to obtain 44.5 parts of a mixture of2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylic acid, methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate and3,3-dimethyl-4-(2',2'dichlorovinyl)-4-butanolide.

To this mixture was added 0.2 part of concentrated sulfuric acidtogether with 200 parts of methanol and the mixture was heated, followedby distillation to remove the methanol. Gas chromatographic analysis ofthe residue revealed that it was a mixture of 29.9 parts of methyl2,2-dimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate (yield 67%;cis/trans ratio=25:75) and 10.4 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 25%). Thismixture was then subjected to distillation under reduced pressure toobtain 28.1 parts of methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate (bp: 67°-69° C./0.2 mmHg) and 9.2 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (b p: 94°-97° C./0.4mmHg).

The latter product 3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide(9.2 parts) was treated with 10 parts of a methanolic solution ofhydrogen chloride (concentration of hydrogen chloride: about 50%),whereby 11.0 parts of methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate (bp: 80°-82° C./0.3 mmHg) was obtained (yield 96% based on3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide).

The methyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate thus obtained wastreated in the same manner as Example 19. By the above procedure wasobtained the desired methyl 2,2-dimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate in a yield of about 90%.

EXAMPLE 23

The procedure of Example 19 was repeated except that ethyl2,3,3-trimethyl-4,6,6-trichloro-5-hexenoate was used in lieu of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate and that potassium hydroxidewas used in lieu of sodium hydroxide. In the first place, 28.8 parts ofethyl 2,3,3-trimethyl-4,6,6-trichloro-5-hexenoate was treated with 8.4parts of potassium hydroxide in 80 parts of methanol to obtain 22.6parts of a mixture of 1,2,2-trimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylic acid, methyl1,2,2-trimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate and2,3,3-trimethyl-4-(2',2'-dichlorovinyl)-4-butanolide.

To this mixture was added 0.1 part of p-toluenesulfonic acid togetherwith 100 parts of ethanol and the mixture was heated. The ethanol wasthen distilled off. Gas chromatographic analysis of the residue revealedthat it was a mixture of 8.3 parts of ethyl1,2,2-trimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate (yield33%) and 13.8 parts of2,3,3-trimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 62%). Thismixture was then subjected to column chromatography (silica gel;elute=n-hexanebenzene=1:1) to isolate 7.5 parts of ethyl1,2,2-trimethyl-3-(2',2'dichlorovinyl) cyclopropanecarboxylate (NMR,δ:1.04 (s), 1.13 (s), 1.18 (s), 1.23 (t, J=7 Hz) 12 H; 2.25 (d, J=8 Hz)1H; 4.08 (q, J=7 Hz) 2 H; 5.57 (d, J=8 Hz), 6.30 (d, J=8 Hz) 1H) and12.7 parts of 2,3,3 -trimethyl-4-(2',2'-dichlorovinyl)-4-butanolide(NMR,δ: 0.78-1.17 (m) 9 H; 2.07-2.53 (m) 1H; 4.71 (d, J=9 Hz), 4.74 (d,J=9 Hz) 1 H; 5.93 (d, J=9 Hz), 5.99 (d, J=9 Hz) 1 H; m p: 58° C.).

Then, the latter product2,3,3-trimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (12.7 parts) wastreated with 30 parts of an ethanolic solution of hydrogen chloride(concentration of hydrogen chloride: about 45%) to obtain 14.2 parts ofethyl 2,3,3-trimethyl-4,6,6-trichloro-5-hexenoate (b p: 104°-106° C./0.4mmHg; NMR (100 MHz) δ: 1.20 (t, J=9 Hz), 0.9-1.3, 12 H; 2.4-2.7 (m) 1 H;4.01 (q, J=7 Hz), 4.03 (q, J=7 Hz) 2 H; 4.63 (d, J=11 Hz), 4.78 (d, J=11Hz) 1 H; 5.96 (d, J=11 Hz), 5.97 (d, J=11 Hz) 1 H; IR (liquid film):1610 cm⁻¹ (C═C), 1730 cm⁻¹ (CO)).

With the above ethyl 2,3,3-trimethyl-4,6,6-trichloro-5- hexenoate as astarting material, the procedure described above was repeated to obtainethyl 1,2,2-trimethyl-3-(2',2'-dichlorovinyl) cyclopropanecarboxylate.

In this manner, the 2,3,3-trimethyl-4-(2',2'-dichlorovinyl)-4-butanolideconcomitantly produced was converted to ethyl2,3,3-trimethyl-4,6,6-trichloro-5-hexenoate, from which an additionalamount of ethyl 1,2,2-trimethyl-3-(2',2'-dichlorovinyl)cyclopropanecarboxylate was obtained.

REFERENCE EXAMPLE 1

To a mixed solution of 12.0 parts of sodium hydroxide, 40 parts of waterand 60 parts of methanol was added dropwise under reflux 31.0 parts ofethyl 3,3-dimethyl-4,6,6,6-tetrachlorohexanoate and, after the dropwiseaddition had been completed, the mixture was stirred at that temperaturefor 2 hours. The reaction mixture was then distilled under reducedpressure to remove the methanol, and the residue was neutralized withhydrochloric acid and extracted with diethyl ether. From this etherlayer was obtained 19.2 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 92%) which hadthe following properties.

b p: 94°-97° C./0.4 mmHg

IR spectrum (liquid film): 1620 cm⁻¹ (C═C), 1785 cm⁻¹ (CO)

Mass spectrum: m/e (M⁺) 208,210,212

NMR spectrum,δ: 1.01 (s) 3 H, 1.19 (s) 3 H, 2.13 (d, J=17 Hz) 1 H, 2.43(d, J=17 Hz) 1 H, 4.78 (d, J=9 Hz) 1 H, 5.95 (d, J=9 Hz) 1 H

Elemental analysis (Calcd. values in parentheses): C, 46.24 (45.96) %,H, 5.09 (4.82) %

REFRENCE EXAMPLE 2

The procedure of Reference Example 1 was repeated except that 35.4 partsof ethyl 3,3-dimethyl-4-bromo-6,6,6-trichlorohexanoate was used in lieuof ethyl 3,3-dimethyl-4,6,6,6-tetrachlorohexanoate. By this procedurewas obtained 19.0 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide (yield 90%).

REFERENCE EXAMPLE 3

To a mixed solution of 6.0 parts of sodium hydroxide, 40 parts of waterand 60 parts of methanol was added dropwise under reflux 26.0 parts ofmethyl 3,3-dimethyl-4,6,6-trichloro-5-hexenoate and, after the dropwiseaddition had been completed, the mixture was further stirred underreflux for 2 hours. The reaction mixture was then treated in the samemanner as Reference Example 1 to obtain 19.5 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl-4-butanolide (yield 93%).

The above procedure was repeated except that 27.4 parts of ethyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate was used in lieu of methyl3,3-dimethyl-4,6,6-trichloro-5-hexenoate. In this case, 19.8 parts of3,3-dimethyl-4-(2',2'-dichlorovinyl)-4-butanolide was obtained (yield95%).

EXAMPLE 24

To a mixture of 23.2 parts of 2-methyl-5,5,6-trichloro-2-heptene-4-oland 32.4 parts of ethyl orthoacetate was 1.0 part of isobutyric acid.The mixture was stirred under a nitrogen atmosphere at 140°-160° C. for8 hours while the byproduced ethanol was continuously removed from thereaction system. Then, the reaction solution was directly subjected todistillation under reduced pressure to obtain 26.8 parts of oilyfraction (bp: 120°-135° C./0.4 mmHg). Gas chromatographic analysis ofthe fraction revealed that it was a mixture of 20.5 parts of ethyl3,3-dimethyl-4,6,7-trichloro-5-octenoate (Mass spectrum: m/e(M⁺) 300,yield 68%) and 5.4 parts of3,3-dimethyl-4-(2',3'-dichloro-1'-butenyl)-4-butanolide (Mass spectrum:m/e(M⁺) 236, yield 23%).

Then, 26.8 parts of the above mixture was dissolved in 100 parts ofethanol and, hydrogen chloride gas was bubbled into the solution at roomtemperature for one hour. It was confirmed by gas chromatography that3,3-dimethyl-4-(2',3'-dichloro-1'-butenyl)-4-butanolide was no longerdetectable in the reaction solution and converted to ethyl3,3-dimethyl-4,6,7-trichloro-5-octenoate. The low fraction was distilledoff and the residue was further distilled under reduced pressure toobtain 26.5 parts of ethyl 3,3-dimethyl-4,6,7-trichloro-5-octenoate(yield 88% based on starting 2-methyl-5,5,6-trichloro-2-heptene-4-ol),the properties of which are given below.

bp: 122°-124° C./0.45 mmHg

IR spectrum (neat): 1730 cm¹ (CO), 1640 cm¹ (C═C)

NMR spectrum,δ(ppm): 1.08(s), 1.21(t,J=7 Hz)9H; 1.65(d,J=6.5 Hz)3H;2.15(d,J=15 Hz), 2.46(d,J=15 Hz)2H; 4.07(q,J=7 Hz)2H; 4.45-4.75(m)1H;4.94(d,J=10.5 Hz)1H; 6.05(d,J=10.5 Hz)1H

We claim as our invention:
 1. A method of producing aγ-halogeno-δ-unsaturated carboxylic acid ester of the general formula:##STR20## which comprises reacting a γ-lactone derivative of the generalformula: ##STR21## with a hydrogen halide of general formula HX and analcohol of general formula R⁴ OH, wherein R¹ and R², respectively, meanan alkyl group of 1 to 5 carbon atoms; R³ is selected from the groupconsisting of hydrogen, alkyl groups of 1 to 5 carbon atoms andcycloalkyl groups of 3 to 8 carbon atoms; R⁴ is an alcohol residueselected from the group consisting of alkyl, cycloalkyl, alkenyl,cycloalkenyl, alkynyl, ##STR22## wherein R⁵ is selected from the groupconsisting of hydrogen and methyl; R⁶ is selected from the groupconsisting of alkenyl, alkadienyl, alkynyl and benzyl, ##STR23## whereinR⁷ is selected from the group consisting of hydrogen, ethynyl and cyano;R⁸ is selected from the group consisting of hydrogen, halogen and alkyl;R⁹ is selected from the group consisting of halogen, alkyl, alkenyl,alkynyl, benzyl, thenyl, furylmethyl, phenoxy and phenylthio; R⁸ and R⁹,taken together, may form a polymethylene chain which may be intertuptedby a sulfur or oxygen atom; Q is a member selected from the groupconsisting of --O--, --NH--, --S-- and --CH═CH--; n is 1 or 2, A--CH₂ --wherein A is selected from the group consisting of phenoxyphenyl,phthalimide, thiophthalimids, di- or tetrahydrophthalimido anddialkylmaleimido and ##STR24## wherein R¹⁰ is selected from the groupconsisting of phenyl, thienyl and furyl; B is a halogen atom; and X andY are halogen atoms which may be the same or different.
 2. A methodaccording to claim 1 wherein said γ-lactone derivative is represented bythe general formula: ##STR25## wherein R^(3') is a member selected fromthe group consisting of hydrogen and alkyl groups of 1 to 5 carbonatoms; and Xs are the same or different and each means a halogen atom.3. A method according to claim 1 wherein said alcohol is an alkanol of 1to 4 carbon atoms.
 4. A method according to claim 1 wherein said alcoholis used in a proportion of at least 0.5 times the stoichiometricrequirement for a ring-opening esterification of said γ-lactonederivative.
 5. A method according to claim 4 wherein the amount ofalcohol is 0.5 to 10 times the stoichiometric requirement for aring-opening esterification of said γ-lactone derivative.
 6. A methodaccording to claim 5 wherein the amount of alcohol is 1.5 to 7 times thestoichiometric requirement for a ring-opening esterification of saidγ-lactone derivative.
 7. A method according to claim 1 wherein saidhydrogen halide is used in an amount corresponding to 0.5 to 10 timesthe stoichiometric requirement for a ring-opening reaction of saidγ-lactone derivative.
 8. A method according to claim 7 wherein theproportion of hydrogen halide is 1.3 to 5 times the stoichiometricrequirement for a ring-opening reaction of said γ-lactone derivative. 9.A method according to claim 1 wherein the ring-opening reaction of saidγ-lactone derivative is conducted at temperatures in the range of 0° to150° C.
 10. A method according to claim 1 wherein the unsaturatedcarboxylic acid ester is produced in a yield of at least about 90%. 11.A method for producing a cyclopropanecarboxylic acid ester of thestructural formula: ##STR26## which comprises (i) reacting a γ-lactonederivative of the structural formula: ##STR27## with a hydrogen halideof general formula HX and an alcohol of general formula R⁴ OH to obtainγ-halogeno-δ-unsaturated carboxylic acid ester of the structuralformula: ##STR28## and (ii) treating the so obtained ester with a basicreagent, wherein each of the above formulae R¹ and R² is lower alkylhaving from 1 to 5 carbon atoms; R³ is a member selected from the groupconsisting of hydrogen, lower alkyl having from 1 to 5 carbon atoms andcycloalkyl having from 3 to 8 carbon atoms; R⁴ is an alcohol residueselected form the group consisting of alkyl, cycloalkyl, alkenyl,cycloalkenyl, alkynyl; ##STR29## where R⁵ is selected from the groupconsisting of hydrogen and methyl; R⁶ is selected from the groupconsisting of alkenyl, alkadienyl, alkynyl and benzyl; ##STR30## whereinR⁷ is selected from the group consisting of hydrogen, ethynyl and cyano;R⁸ is selected from the group consisting of halogen, alkyl, alkenyl,alkynyl, benzyl, thenyl, furylmethyl, phenoxy and phenylthio; R⁸ and R⁹,taken together, may form a polymethylene chain which may be interruptedby a sulfur or oxygen atom; Q is a member selected from the groupconsisting of --O--, --NH--, --S-- and --CH═CH--; n is 1 or 2, A--CH₂ --wherein A is selected from the group consisting of phenoxyphenyl,phthalimido, thiophthalimido, di- or tetrahydrophthalimido anddialkylmaleimido and ##STR31## wherein R¹⁰ is selected from the groupconsisting of phenyl, thienyl and furyl; B is a halogen atom; and X andY are halogen atoms which may be the same or different.
 12. A methodaccording to claim 11, wherein the γ-halogeno-δ-unsaturated carboxylicacid ester of the structural formula ##STR32## is obtained in a yield ofat least 90%.
 13. A method according to claim 11, wherein said alcoholis a lower alkanol having from 1 to 4 carbon atoms.
 14. A methodaccording to claim 11, wherein said alcohol is used in a proportion ofat least 0.5 times the stoichiometric requirement for a ring-openingesterification of said γ-lactone derivative.
 15. A method according toclaim 14 wherein the amount of alcohol is 1.5 to 7 times thestoichiometric requirement for a ring-opening esterification of saidγ-lactone derivative.
 16. A method according to claim 11 wherein saidhydrogen halide is used in an amount corresponding to 0.5 to 10 timesthe stoichiometric requirement for a ring-opening reaction of saidγ-lactone derivative.
 17. A method according to claim 16 wherein theproportion of hydrogen halide is 1.3 to 5 times the stoichiometricrequirement for a ring-opening reaction of said γ-lactone derivative.18. A method according to claim 11 wherein the ring-opening reaction ofsaid γ-lactone derivative is conducted at temperatures in the range of0° to 150° C.
 19. A method according to claim 11 wherein said basicreagent is used in a proportion of 0.3 to 7 moles per mole of thestarting material ester.